While playing the Binding of Isaac, I should have died when fighting Monstro II, but instead I got a message on a blue screen saying (I think): "Today is a bad day to have a castle". It gave me half a heart back and changed Isaac into a demon for about 5 seconds. Is that normal, and if it is what item is it?

Are you sure you were supposed to die? Since damage from most sources only takes off half a heart, you would have ended with your last half heart eventually, which is the trigger for the Whore of Babylon item. Also, what exactly happened after 5 seconds? The transformation you described only reverts once you leave the room, to my best of knowledge.
–
AubergineJan 9 '13 at 6:21

The transformation only reverts if you leave the room with more than half a heart
–
murgatroid99Jan 9 '13 at 19:22

1 Answer
1

As Yves's comment points out, the only item that is even somewhat similar to what you describe is the Whore of Babylon. The item itself looks like this:

You can get it either by picking it up during your playthrough or by choosing to play as Eve. If you have this item and you have exactly half a heart left, it gives the message "What a horrible night to have a curse..." and turns you into a demon figure like in the following picture:

As the wiki article states, you revert to your original appearance when you leave a room with more than half of a heart.

Murgatroid99, that is what happened but after 5 seconds (about) I changed back into isaac, but that was also when i beat the boss. Would that have triggered it to end? Also yes aubergine it should have killed me.
–
KalJan 9 '13 at 21:49

Are you sure it was when you beat the boss and not when you exited the boss room? And if the demon appearance you saw was the same as the one in the question then there is nothing else in the game that could have caused it.
–
murgatroid99Jan 9 '13 at 21:51

Actually in my most recent run i found out that tarot card III The Empress causes the same effect, (I did not have it at the time) And i am positive that it was when i beat the boss.
–
KalJan 9 '13 at 22:29

Oh, you're right, I forgot about the tarot card, but of course that would be inconsistent with your description that the transformation was caused by health loss. And the fact is that no item in the game is consistent with all of what you described, but the Whore of Babylon is the closest to what you described and if the demon you became looks like the one in my answer, it must have been that.
–
murgatroid99Jan 9 '13 at 22:35

I think it was too. I may have picked up a heart. Is it possible it could have changed me back in the middle of the room? Thank you for all of the help.
–
KalJan 9 '13 at 22:55